Sex Pheromone of Anastrepha striata.

The guava fruit fly, Anastrepha striata, is a pest of several cultivated species of Myrtaceae in the American tropics and subtropics. During calling, A. striata males release numerous volatiles. This study was conducted to identify which of the male volatiles function as the A. striata sex pheromone and to investigate the effects of age and time of day on the emission of pheromone components. Analysis of the volatiles from males collected by solid phase microextraction using gas chromatography coupled to electroantennographic detection (GC-EAD) showed that three volatile compounds elicited repeatable responses from the antennae of females. The EAD-active compounds were identified by GC/mass spectrometry as ethyl hexanoate, linalool, and ethyl octanoate. In two-choice tests using Multilure traps placed in field cages, traps baited with live males, ethyl hexanoate, or the three-component blend captured more females than unbaited traps. However, there was no difference in catches when traps baited with live males were compared against traps baited with ethyl hexanoate. Although traps baited with the three-component blend caught more females than traps baited with live males, the difference was not significant. Analyses of pheromonal components released by A. striata males 8 to 26 days old showed that there was an effect of age on pheromone production and also a significant effect of time of day on pheromone emission. Release of the volatile compounds occurred from 14.00 to 18.00 hr, although traces of linalool were detected from 08.00 hr. Peak emission of pheromone compounds occurred at 14.00 hr.